Biases and errors in individuals'judgments about their health are a major concern in health services research. Furthermore, the adequate delivery and evaluation of health services is jeopardized when patients are unable to accurately recall medical information. Six experiments are proposed to examine sources of recall and judgment errors concerning personal health. The cognitive processes studied are the overconfidence bias and the self-- enhancement bias. All of the studies will utilize adult members of this community. In each study, participants will be asked to provide judgments about their cholesterol. After their cholesterol is measured and communicated to them, we will telephone the participants at various intervals and ask them to recall their reading. The experiments proposed test the impact of a variety of theoretically-derived variables on a) participants'judgments of the probability that their cholesterol is elevated, b) participants' short-term and long-term ability to recall their cholesterol readings, c) the relationship between diagnostic status and recall accuracy, and d) interventions to reduce biases in judgment and errors in recall.